The present invention relates to a dishwasher, and more particularly to a dishwashing machine of the type for home use and containing an electrochemical cell capable of producing an oxidizing agent for the cleaning and disinfecting of dishes and, at the same time, eliminating disagreeable odors therefrom.
There is known a dishwashing machine wherein a salt container or brine tank can selectively supply brine solution not only to a water decalcifier or softener to achieve regeneration thereof, but also to an electrochemical cell. Electrolysis of sodium chloride solution, i.e. brine, within this electrochemical cell, during brief periods of the operating cycle of the machine, produces sodium hypochlorite which is introduced in measured quantities into the wash tank of the machine by means of a suitable piston driven metering unit. The sodium hypochlorite is diluted in a relatively large quantity of water which is passed into the tank, and the solution is sprinkled onto dishes within the wash tank in order to disinfect the dishes and to complete the cleaning thereof.
Since the sodium hypochlorite, as mentioned above, must be diluted in water, it is necessary that the electrochemical cell produce the sodium hypochlorite during each operating period in precisely the correct amount, i.e. normally a few grams, in order to obtain in the solution formed in the wash tank a sodium hypochlorite concentration sufficient to produce a satisfactory oxidizing effect on the dishes. To accomplish this, the overall dimensions of the electrochemical cell must be inversely proportional to its efficiency.
It is a well known fact that in dishwashers for home use it is very important that the overall dimensions of the various components of the machine be limited so that it is possible to take maximum advantage of the small spaces available exterior of the wash tank of the machine. However, in the above discussed prior art types of machine, the use of a large electrochemical cell is necessary since the efficiency of an electrochemical cell for the production of sodium hypochlorite decreases considerably when, during electrolysis therein, temperatures slightly above ambient room temperatures are achieved. This problem could be solved by taking measures to cool the electrochemical cell. However, ths provision of a cooling device to achieve temperature control of the electrochemical cell not only would increase the size of the overall machine, but also would complicate the construction of the machine. Additionally, a solution of water and sodium hypochlorite is alkaline so that, as is well known, the sodium hypochlorite cannot produce a fully satisfactory oxidizing effect on the dishes.
However, the main disadvantage of the above discussed prior art type of dishwashing machine is due to the fact that the sodium hypochlorite solution introduced into the wash tank inevitably contains sodium chloride which, as is well known, creates considerable corrosion problems.
A further disadvantage of the above discussed prior art type of machine results from incrustations formed on the electrodes of the electrochemical cell as a result of repeated electrolysis operations by the cell. Over the course of time, such incrustations can prevent the cell, and thus the dishwashing machine, from functioning properly.